Hacking

Presented By :KUMAR ANAND SINGH 04-243,ETC/2008

Why do Hackers Attack ?

Because they can A large fraction of hacker attacks have been

pranks Financial Gain Espionage Venting anger at a company or organization Terrorism

Types of Hacker Attacks

Active Attacks– Denial of Service– Breaking into a site

• Intelligence Gathering• Resource Usage• Deception Passive Attacks

– Sniffing• Passwords• Network Traffic• Sensitive Information

– Information Gathering

Modes of Hacker Attacks

Over the Internet Over LAN Locally Offline Theft Deception

Spoofing

Definition:An attacker alters his identity so that

someone thinks he is some one else

– Email, User ID, IP Address, …– Attacker exploits trust relation

between user and networked machines to gain access to machines

Types of Spoofing

IP Spoofing Email Spoofing Web Spoofing

IP Spoofing – Flying-Blind Attack

Definition:

Attacker uses IP address of another computer to acquire information or gain access

Replies sent back to 10.10.20.30

John

10.10.5.5

From Address: 10.10.20.30

To Address: 10.10.5.5

• Attacker changes his own IP address to spoofed address

• Attacker can send messages to a machine masquerading as spoofed machine

• Attacker can not receive messages from that machine

IP Spoofing – Source Routing

Definition:

Attacker spoofs the address of another machine and inserts itself between the attacked machine and the spoofed machine to intercept repliesSpoofed Address

10.10.20.30

Attacker intercepts packets

as they go to 10.10.20.30

Attacker

10.10.50.50

From Address: 10.10.20.30

To Address: 10.10.5.5

Replies sent back

to 10.10.20.30

John

10.10.5.5

• The path, a packet may take can vary over time • To ensure that he stays in the loop the attacker uses

source routing to ensure that the packet passes through certain nodes on the network

E-mail Spoofing

Definition: Attacker sends messages masquerading as

some one else What can be the repercussions?

Types of Email Spoofing

Create an account with similar email address Modify a mail client

Attacker can put in any return address he wants to in the mail he sends

Telnet to port 25Most mail servers use port 25 for SMTP (Simple

Mail Transfer Protocol). Attacker logs on to this port and composes a message for the user.

Web Spoofing

Basic – Attacker registers a web address matching

an entity e.g. voteforbush.com, getproducts.com.

Man-in-the-Middle Attack– Attacker acts as a proxy between the web

server and the client– Attacker has to compromise the router or a

node through which the relevant traffic flows

Contd.

URL Rewriting– Attacker redirects web traffic to another

site that is controlled by the attacker– Attacker writes his own web site address

before the legitimate link Tracking State

– When a user logs on to a site a persistent authentication is maintained

– This authentication can be stolen for masquerading as the user

Web Spoofing

Session HijackingDefinition:

Process of taking over an existing active session

Modus Operandi:1. User makes a connection to the server by

authenticating using his user ID and password.2. After the users authenticate, they have access

to the server as long as the session lasts.3. Hacker takes the user offline by denial of

service4. Hacker gains access to the user by

impersonating the user

Session Hijacking

Bob telnets to Server

Bob authenticates to Server

Hi! I am BobDie!Bob

Attacker

Attacker can – monitor the session– periodically inject commands into session– launch passive and active attacks from the

session

Denial of Service Attack (DOS)

Definition:Attack through which a person can render a system unusable or significantly slow down the system for legitimate users by overloading the system so that no one else can use it.

Types of DOS Attacks Crashing the system or network

Send the victim data or packets which will cause system to crash or reboot.

Exhausting the resources by flooding the system or network with information

Since all resources are exhausted others are denied access to the resources

Distributed DOS attacks are coordinated denial of service attacks involving several people and/or machines to launch attacks

Buffer Overflow Attacks This attack takes advantage of the way

in which information is stored by computer programs

An attacker tries to store more information on the stack than the size of the buffer

Programs which do not do not have a rigorous memory check in the code are vulnerable to this attack

Password Attacks A hacker can exploit a weak passwords &

uncontrolled network modems easily Steps

– Hacker gets the phone number of a company

– Hacker runs war dialer program

– Hacker now needs a user id and password to enter company network

Password Security

Client ServerCompare

PasswordHashed

Password

Stored Password

Hash

Function

Hashed

Password

Password

Allow/Deny Access

Password hashed and stored– Salt added to randomize password & stored on system

Password attacks launched to crack encrypted password

Salt

Thank You